The present inventor applied for a Chinese invention patent titled an injector for automatically mixing powder for injection on Sep. 14, 2005, and its publication date is May 17, 2006. An injector for automatically mixing powder for injection, comprising a solvent bottle, a solute bottle, a needle cap, a solute bottle sleeve, a solvent bottle sleeve, a turntable sleeve, first impelling sleeve and second impelling sleeve, said solute bottle is set inside said solvent bottle sleeve, said solvent bottle, the first and second impelling sleeve are set inside said solvent bottle sleeve, said turntable sleeve is sleeved outside said solvent bottle sleeve, and said solute bottle sleeve and solvent bottle sleeve are connected together in a up and down position. The turntable sleeve drives said first and second impelling sleeve to move along the first impelling and second impelling restrict slot respectively, then the needle of said needle cap firstly penetrate the glue tampon of said solute bottle and locate therein, then penetrate the glue tampon of said solvent bottle, the solvent in the solvent bottle flow into said solute bottle under the pressure, so the powder for injection can be mixed automatically. There are a first impelling restrict slot, second impelling restrict slot and a location card of said turntable sleeve reside at the inner wall of said turntable sleeve, the strike line of said first and second restrict slot is of spiral shape or may be an arc with certain angle. However, there are some drawbacks in the above technology: firstly, the manufacturing process may be complex and costs a lot, because it requires a high precession when making the spiral shape or an arc with certain angle of the first and second restrict slot at the inner wall of turntable sleeve; secondly, the structure of said injector is complex and may be difficult to assemble because too many sleeves are needed, including solute bottle, solvent bottle and turntable bottle.